Using a dyadic game theory paradigm, three experiments on the social dilemma of trust were conducted over the Internet in real time, involving real money. It was predicted and found that in-group favouritism in trusting behaviour was contingent on historical relationships between societies. In the China-Japan experiment, mainland Chinese but not Japanese trusted and made fair allocations to in-group members more than out-group members, and out-group trust was best predicted by positive stereotypes of the out-group for Chinese and identity for Japanese. In the China-Taiwan experiment, Taiwanese but not Mainland Chinese trusted in-group members more than out-group members, and in-group trust for Taiwanese was best predicted by perceptions of current realistic threats. In the Taiwan-Japan experiment, there were slight in-group favouring tendencies in trust, and positive stereotypes of the out-group were the best predictors of out-group trust. Japanese were unique in not displaying in-group favouring behaviour at all, whereas both Chinese and Taiwanese were context specific in their in-group favouritism. Stereotypes, social identities, perceptions of realistic threat, and historical anger made significant contributions to predicting trusting behaviour, but overall these survey measures only accounted for small and inconsistent amounts of variance across the three experiments.